In many printed works, e.g., catalogs, there are reproductions of a color photograph of an object with a plain background surrounding the object. As the term "object" is employed herein, it might be animate or inanimate and pertains to that part of the original photograph that is to be retained in the final reproduction. The plain background referred to might or might not be colored. The present practice employed in arriving at such a printed reproduction of an object commences with the photographing of the object on positive, color film. Then a "mask", or more correctly a "photo-mechanical drop-out mask", is produced on film. In this mask the areas corresponding to the location of the object (or parts thereof) are transparent while the remainder is opaque.
Present commercial practices generally involve one of two procedures for making the mask. In one a second photograph is taken at the same general time that the positive is made. This second photograph is made on a negative film having no range of values (high contrast). In the other procedure the initial positive is put on a scanner which produces a second positive (thus permitting an artist to touch up the second positive, as hereinafter discussed), and a negative subsequently is made from the second positive.
After the drop-out mask is produced it and the original positive photograph are put on a scanner (or employed in any other customary method used in making color separations) which then makes the color separations employed in the printing process. A scanner has a light transmitting surface (usually cylindrical) against which the photograph and mask are positioned at separate locations. Light is shown through the two and converted into electrical signals which are then employed, with such modifications as to size, etc., as desired, to produce the separations. Such devices are well known in the art.
Two problems have plagued the industry in the production of the mask. One of these is loss of detail. For example, assume that a photograph of a bicycle is being made for a catalog. The spokes of the wheels of the bicycle appear as fine lines. The mask must block out everything around these fine lines. The conventional processes often lose such details and it is necessary for an artist to reapply such details to the negative mask. This is a very tedious and time-consuming operation. Consequently, it is expensive. Furthermore, it usually requires that the photographs be made oversize as compared to the size of the reproductions that are to be ultimately printed. By making the photographs initially large, the artist has an easier time of reinserting the details that may have been lost in the mask. The size can be adjusted downwardly as required in the production of the separations in the scanner. However, due to the fact that they are large they occupy more of the scanning surface in the scanner thus limiting the number of photographs that can be processed simultaneously in the scanner. In other words, a number of small photographs can normally be put in the scanner in the same space occupied by one large one and color separations produced for each of the small photographs simultaneously.
The other of the problems occurs primarily in the procedure wherein a second photograph on high contrast film is taken at the same time that the color photograph to be reproduced is taken. The two films, being of different characters, will not always end up with exactly the same dimensions after the development process. The error in size between the two may at one time be relatively minor and the next time be very substantial. When the error is very minor, procedures employed in connection with the scanning operation may permit its correction. However, a major error cannot be tolerated. Until the mask has been completed and compared with the positive photograph, a photographer never knows just what kind of an error situation he may have. This may be two hours or more. Since a substantial error will require the taking of additional photographs, the photographer normally will feel that he must maintain his photographic setup until the films can be compared. This is tying up his studio layout and thus is costly to the photographer in terms of efficient production. Furthermore, invariably there is little available time between the deadline for the completion of a catalog and the date when the order is given to the photographer to produce the photographs. With little time available, the delays involved in repeating photographic operations can be deadly. Under present commercial practices, it is not uncommon to have only about forty percent of the photographs taken to be within acceptable tolerances so far as size variation is concerned.
In the process devised by me, at the same time (immediately before or after) the color film is exposed for the purpose of making the positive film, a second exposure is made on the same type of film but with the object being photographed being essentially only back-lighted. Thus the second exposure produces a silhouette of the object on the color film. The two units of the color film bearing these two exposures are processed simultaneously. Thus, there is no possibility for variations in processing conditions which might otherwise cause errors in the size of the object images appearing upon the two units of film. The silhouette photograph is then employed to produce a drop-out mask on a high contrast film.
The use of my procedure will reduce the occurrence of size errors between the mask and the positive photograph to something like three percent of the photographs taken. The resulting mask will have substantially all of the required details without the necessity for an artist reinserting detail. Since the operations previously performed by an artist are no longer necessary, the photographs may be made substantially smaller thus permitting a number of them to be put into the scanner simultaneously.